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This page provides a key to interpreting symbols and units in Introductory Electricity & Magnetism, and provides values of constants in SI units.
| Symbol | Name | Meaning in Physics 102 |
|---|---|---|
| \( \gamma \) | gamma | Symbol for high-energy EM wave |
| \( \Delta \) | Delta | Symbol for change in a quantity |
| \( \epsilon \) or \( \varepsilon \) | epsilon | Electric polarizability of a material ("permittivity") Careful: Similar to emf symbol \( \mathcal{E} \) |
| \( \theta \) | theta | Angle |
| \( \kappa \) | kappa | Dielectric constant of a material |
| \( \lambda \) | lambda | Wavelength |
| \( \mu \) | mu | Linear (charge) density OR Magnetization in a material in a magnetic field |
| \( \pi \) | pi | The ratio of a circle's circumference to its diameter |
| \( \rho \) | rho | Volume (charge) density |
| \( \sigma \) | sigma (lower case) | Area density or Blackbody radiation constant |
| \( \Sigma \) | Sigma (upper case) | The sum of the following quantity |
| \( \tau \) | tau | Symbol for torque OR Symbol for time constant in a circuit |
| \( \phi \) | phi (lower case) | Angle |
| \( \Phi \) | Phi (upper case) | Symbol for flux |
This section uses the placeholder variable \( A \). You may use any relevant variable in its place.
| Symbol | Meaning | Use/Definition |
|---|---|---|
| \( \Delta \) | Change | \( \Delta A =A_{final}-A_{initial} \) |
| \( \sum{} \) | Sum | For a series of quantities \( A_1 \), \( A_2 \), \( A_3 \), etc., \( \sum A =A_{1}+A_{2}+A_{3}+\cdots \) |
| \( \vec{A} \) | Vector symbol | The variable represents a vector quantity with magnitude and direction. May also be drawn with partial arrow \( \stackrel{\rightharpoonup}{A} \) |
| \( |\vec{A}| \) | Vector magnitude | The magnitude of the vector \( \vec{A} \) If \( \vec{A} \) is known to be a vector, the magnitude may also be written as \( A \) |
| \( A_x \) | x-component of vector A | The projection of the vector \( \vec{A} \) (magnitude and direction) onto the x axis. Similarly, \( A_y \) and \( A_z \) are the projections of \( \vec{A} \) onto the y and z axes, respectively. |
| \( A_\parallel \) | Parallel component notation | The component of vector \( \vec{A} \) that is parallel to a second reference vector. |
| \( A_\perp \) | Perpendicular component notation | The component of vector \( \vec{A} \) that is perpendicular to a second reference vector. |
| \( A(x) \) | \( A \) as a function of the variable \( x \) | An expression for the value of \( A \) for any input value of the variable \( x \). Be careful: \( A(x) \) does not mean \( A\times x \) |
| \( A_0 \) | Initial value of \( A \) | Typically, the value of \( A \) when \( t=0 \). In function format, \( A(t=0)=A_0 \) May be said as "A naught". |
| \( \arccos(A) \) or \( \cos^{-1}(A) \) | Inverse cosine of \( A \) Similar for other trigonometric functions. | Inverse of the cosine function. Finds the value of \( \theta \) that gives \( \cos(\theta)=A \) May appear as "acos" on some calculators. |
Introductory Physics uses meters, kilograms, and seconds as its base SI units (sometimes called 'mks'). When calculating, most units should be converted to their 100 form (no prefix). However, kilograms should be converted to the 103 form. Whenever you're not sure, check the units in the constant(s) you are using for calculations.
| Power | Prefix | Symbol |
|---|---|---|
| \( 10^{12} \) | tera | T |
| \( 10^{9} \) | giga | G |
| \( 10^{6} \) | mega | M |
| \( 10^{3} \) | kilo | k |
| \( 10^{0} \) | — | — |
| \( 10^{-2} \) | centi | c |
| \( 10^{-3} \) | milli | m |
| \( 10^{-6} \) | micro | μ |
| \( 10^{-9} \) | nano | n |
| \( 10^{-12} \) | pico | p |
These constants will be used in calculations. You do not need to memorize them.
| Name | Symbol | Value |
|---|---|---|
| Gravity of Earth | \( g \) | \( 9.8\mbox{ m/s}^2 \) |
| Gravitational Constant | \( G \) | \( 6.67\times 10^{-11}\mbox{ m}^3/\mbox{kg}\,\mbox{s}^2 \) |
| Electron charge | \( e \) | \( 1.6\times 10^{-19}\mbox{ C} \) |
| Electron mass | \( m_e \) | \( 9.11\times 10^{-31}\mbox{ kg} \) \( 511\mbox{ keV}/\mbox{c}^2 \) |
| Proton mass | \( m_p \) | \( 1.673\times 10^{-27}\mbox{ kg} \) \( 938\mbox{ keV}/\mbox{c}^2 \) |
| Neutron mass | \( m_n \) | \( 1.675\times 10^{-27}\mbox{ kg} \) \( 939.5\mbox{ keV}/\mbox{c}^2 \) |
| Coulomb constant | \( k \) | \( 8.99\times 10^{9}\mbox{ N}\,\mbox{m}^2/\mbox{C}^2 \) Alternatively, \( k=\frac{1}{4\pi\varepsilon_0} \) |
| Permittivity of free space | \( \varepsilon_0 \) | \( 8.85\times 10^{-12}\mbox{ C}^2/\mbox{N}\,\mbox{m}^2 \) |
| Magnetic permeability of free space | \( \mu_0 \) | \( 1.257\times 10^{-6}\mbox{ T}\,\mbox{m}/\mbox{A}^2 \) \( 4\pi\times 10^{-7}\mbox{ T}\,\mbox{m}/\mbox{A}^2 \) |
| Speed of light in vacuum | \( c \) | \( 3\times 10^{8}\mbox{ m}/\mbox{s} \) Alternatively, \( c=\frac{1}{\sqrt{\varepsilon_0 \mu_0}} \) |
| Planck constant | \( h \) | \( 6.626\times 10^{-34}\mbox{ J}\,\mbox{s} \) |
| Electron volt (unit conversion) | \( eV \) | \( 1\mbox{ eV}=1.6\times 10^{-19}\mbox{ J} \) |